Absorbent article comprising an absorbent element comprising a liquid absorbent thermoplastic composition

ABSTRACT

The present invention relates to absorbent articles, typically for feminine protection, including a topsheet, a backsheet and an absorbent element positioned between the tospheet and the backsheet, said absorbent element includes a fluid storage layer which a liquid absorbent thermoplastic composition. The absorbent thermoplastic composition is a polymeric base material having particles of water-insoluble water-swellable absorbent material dispersed therein. The liquid absorbent thermoplastic composition is configured in a plurality of unattached spaced apart zones.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.10/669,610 filed Sep. 23, 2003.

FIELD OF THE INVENTION

The present invention relates to absorbent articles in particulararticles for feminine protection like sanitary napkins and panty liners,which comprise an absorbent element comprising a liquid absorbentthermoplastic composition comprising a thermoplastic polymeric basematerial having particles of water-insoluble water swellable absorbentmaterial dispersed therein, the liquid absorbent thermoplasticcomposition being configured in a plurality of unattached spaced apartzones.

BACKGROUND OF THE INVENTION

Although absorbent articles, such as sanitary napkins or panty liners,have improved a lot the last years with respect to various features likeprotection and comfort in use, there is still a consumer need forfurther improvements in these two directions.

Indeed, there exists a real consumer need for absorbent articles,typically for feminine protection articles, having improved liquidhandling properties, namely enhanced liquid distribution properties anda liquid capacity high enough for use without consumer fears of leakageor staining especially after prolonged period of wearing time, yet whichare thin and flexible, thereby offering enhanced fit and comfort.

It is thus an object of the present invention to provide absorbentarticles, preferably those for feminine protection, which provideenhanced distribution, absorption and retention of body fluid not onlyupon first contact with body fluid discharge but also upon additionalsubsequent body fluid discharge, thereby making the wearing experiencemore pleasant over prolonged period of time, and hence improvingcomfort. It is another object of the present invention to provide such afeminine protection article which further promotes a continuouslyself-conforming anatomical cooperation of the article to the wearerduring various activities (e.g. sport). It is an additional object ofthe present invention to provide such a feminine protection articlewhich further offers enhanced fit, comfort and a low degree ofawareness.

It has now been found that all above mentioned objects are met byproviding absorbent articles, like sanitary napkins and panty liners,comprising a topsheet, a backsheet and an absorbent element positionedbetween said topsheet and said backsheet, said element comprising astorage layer which comprises a liquid absorbent thermoplasticcomposition. This composition comprises a polymeric base material havingparticles of water-insoluble water swellable absorbent materialdispersed therein, said composition is configured in a plurality ofunattached spaced apart zones.

In one embodiment herein the liquid absorbent thermoplastic compositionhas a total absorption capacity towards saline solution of at least 2grams/gram. In another embodiment herein the liquid absorbentthermoplastic composition represents at least 15% by weight of the totalweight of the absorbent element. Most preferred executions hereincombine this two features.

Advantageously the absorbent articles of the present inventioncomprising a storage layer with said unattached spaced apart zones ofliquid absorbent thermoplastic composition exhibit faster and enhancedfluid distribution as well as enhanced fluid acquisition and retention,this not only upon first contact with body fluid but also especiallywhen submitted to subsequent body fluid discharge versus absorbentarticles being different from the ones of the present invention only inthat they comprise a storage layer made of the same liquid absorbentthermoplastic composition but configured in continuous manner (e.g.,covering in continuous manner almost the whole surface area between thetopsheet and backsheet of the article) as opposed to discontinuous. Theinterstitial area between the unattached spaced apart zones of liquidabsorbent thermoplastic composition (also called herein transportregions) facilitate and promote the flow of body fluid towards saidunattached zones as well as the absorption of body fluid by said zones.In other words, once body fluid reaches the absorbent element, namelythe storage layer, the distribution speed of the body fluid between theunattached zones is higher than the absorbency speed of the waterswellable absorbent material comprised in said zones, resulting therebyin faster and enhanced distribution of fluid in the so-called transportregions of the article. Without to be bound by any theory it is believedthat this is due to the low absorption kinetic of the absorbent materialbeing entrapped into the polymeric base material in comparison to freeabsorbent material. When the absorption speed of absorbent materialbecomes predominant versus the distribution speed of the fluid in the socalled transport regions, the fluids are absorbed by the absorbentmaterial in the unattached spaced apart zones, thereby lowering theamount of fluid present in the transport regions and even emptying saidregions. Hence upon subsequent discharge of body fluid within thearticle, the transport regions are able to fulfill once more theirfunction of fluid distribution, resulting in more effective use of totalamount of absorbent material present in the article. Indeed the gelblocking phenomenon is reduced and hence a better use of totalabsorption capacity of the absorbent material is obtained according tothe present invention. Actually it has surprisingly been found that thefluid acquisition upon subsequent body fluid discharge in the article ofthe present invention is equal or even better than upon first fluiddischarge. Without to be bound by theory it is believed that after thefirst body fluid discharge the absorbent element, namely storage layer,due to its outstanding fluid distribution properties towards increasedeffective total surface area used in the article per the so calledtransport regions and effective fluid absorption and retentionproperties of the storage zones becomes wetted upon enlarged surfacearea, hence more hydrophilic resulting in overall more effective fluidacquisition upon subsequent fluid discharge. In other words, thesubsequent body fluid discharge triggers the acquisition capacity andspeed, the absorbent material being much more available to absorb fluid.

Advantageously the present invention allows for versatility inpositioning of the plurality of unattached spaced apart zones of saidliquid absorbent thermoplastic composition. Indeed the present inventionallows to target the position of the plurality of unattached spacedapart zones and hence of the absorbent material where needed in theabsorbent element/article and hence optimizes the ratio total amount ofabsorbent material and liquid absorption capacity. The total amount ofparticles of water-insoluble water swellable absorbent material presentin said spaced apart zones of the absorbent element will be moreefficiently utilized resulting in improved absorption characteristics ofthe absorbent element. As a result, the absorbent article can beconfigured with a thinner structure which is capable of absorbing largeramount of body fluid and more flexible structure. The thinner and moreflexible structure can in turn provide improved fit and comfort to thewearer.

Advantageously the absorbent element, namely storage layer, of thearticles of the present invention delivers outstanding protection withabsence of water swellable absorbent material particle spillage in bothdry and wet condition. The powder spillage free property of thethermoplastic composition used herein is beneficial for easierprocessability and handling in plant as well as for safety criteria.Also the swollen absorbent material in wet condition is less liable toescape the spaced apart zones of the storage layer. Without to be boundby theory it is speculated that cohesion of polymeric base material isable to maintain location of the absorbent materials also afterswelling, thereby accommodating the increased volume of the swollenmaterial.

Advantageously the use of the liquid absorbent thermoplastic compositionherein fulfill besides the absorption properties also the function ofadhering adjacent/surrounding layers of the article together. Hence theneed of conventional adhesive glue to adhere storage layer to adjacentlayers for example backsheet and topsheet can be avoided.

In an embodiment herein wherein the backsheet of the article is abreathable backsheet, it has been found that the absorbent elementaccording to the present invention, especially for those embodimentswherein the absorbent element comprises, as the storage layer, theliquid absorbent thermoplastic composition described herein configuredin a plurality of unattached spaced apart zones, is particularlyadvantageous as besides above mentioned benefits, its use also resultsin improved air and water vapor permeability of the absorbent articleboth in dry and wet condition.

BACKGROUND ART OF THE INVENTION

Compositions comprising a thermoplastic component and a super absorbentpolymer are known from the art. For example WO99/57201 or WO02/07791describe such compositions and their applications to bond differentlayers of conventional disposable absorbent articles such as diapers,feminine napkins and medical dressings. EP-A-1 013 291 discloses a hotmelt adhesive with super absorbent polymers. The resulting thermoplastichot-melt adhesive material can be used to adhesively bond substratessuch as polymeric films together, as well as to provide additionalliquid absorption capacity to absorbent structures. This adhesivelycoated material is particularly useful in the construction of absorbentproducts such as catamenials. Absorbent articles which include superabsorbent material located in discrete pockets having water-sensitiveand water-insensitive containment structures are known from U.S. Pat.No. 5,433,715.

None of these prior art references discloses nor suggests absorbentarticles, namely hygienic disposable articles for feminine protection,comprising an absorbent element with storage layer comprising a liquidabsorbent thermoplastic composition as presently claimed.

SUMMARY OF THE INVENTION

The present invention encompasses absorbent article, typically forfeminine protection, comprising a topsheet, a backsheet and an absorbentelement positioned between said topsheet and said backsheet, saidelement comprising a storage layer comprising a liquid absorbentthermoplastic composition which comprises a polymeric base materialhaving particles of water-insoluble water swellable absorbent materialdispersed therein, said composition being configured in a plurality ofunattached spaced apart zones. In one execution the composition has atotal absorption capacity towards saline solution of at least 2 g/g. Inanother execution the composition represents at least 15% by weight ofthe total weight of the absorbent element.

All documents cited are, in relevant part, incorporated herein byreference; citation of any document is not to be construed as anadmission that it is prior art with respect to the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top plan view of the garment facing surface of a pantyliner according to the present invention having an absorbent elementwith a storage layer made of a liquid absorbent thermoplasticcomposition as described herein in a multi stripe pattern.

FIG. 2 is a side view of the panty liner of FIG. 1 taken through lineD-D′.

FIGS. 3-9 show top plan view of garment facing surface of alternativepanty liners according to the present invention with storage layer madeof liquid absorbent thermoplastic composition adhered to the backsheetof the liners in various patterns of a plurality of unattached spacedapart zones.

FIG. 10 shows the equipment for Dunk absorption test

DETAILED DESCRIPTION OF THE INVENTION

The term “absorbent article” is used herein in a very broad senseincluding any article able to receive and/or absorb and/or containand/or retain fluids and/or exudates, especially body fluids/bodyexudates. “Absorbent articles” as referred to herein include, without tobe limited to, sanitary napkins, panty liners, incontinence pads,interlabial pads, breast pads, sweat-absorbent underarm pads, collarinserts, baby diapers, adult incontinence diapers, and human wastemanagement devices.

The term “disposable” is used herein to describe articles that are notintended to be launched or otherwise restored or reused as an article(i.e., they are intended to be discarded after a single use and,preferably to be recycled, composted or otherwise disposed of in anenvironmentally compatible manner).

As used herein, the term ‘wearer-facing’ surface refers to the surfaceof the component of the article generally oriented to face the wearerskin and/or mucosal surface during use of the article. As used herein,the term ‘garment facing’ surface refers to the opposite outer surfaceof the article, typically the surface directly facing the garment of awearer, if worn in direct contact with garment.

As used herein, the term ‘body fluids’ refers to any fluid produced byhuman body occurring naturally including for instance perspiration,urine, menstrual fluids, vaginal secretions and the like, oraccidentally like for instance in the case of skin cutting.

In the following, non-limiting embodiments of the present invention, themain elements of the absorbent article are described.

The absorbent article according to the present invention comprisingthree main elements: the topsheet, facing the user of the article duringuse and being preferably liquid pervious in order to allow liquids,particularly body fluids, to pass into the article; the backsheet,providing liquid containment such that absorbed liquid does not leakthrough the article, this backsheet conventionally provides the garmentfacing surface of the article; and the absorbent element sandwichedbetween the topsheet and the backsheet and providing the absorbentcapacity of the article to acquire and retain liquid which has enteredthe article through the topsheet.

Absorbent Element

The absorbent element as meant herein is any element of the article,except the topsheet and backsheet, which have fluid handling properties,including but not limited to, distribution, transfer, wicking,absorption and/or retention properties. According to the presentinvention, the absorbent element can include the following components:(a) an optional primary fluid distribution layer, preferably togetherwith optional additional fluid distribution layers; (b) a fluid storagelayer; (c) an optional fibrous layer underlying the storage layer.

One optional component of the absorbent element according to the presentinvention is a primarily fluid distribution layer. The primarily fluiddistribution layer typically underlies the topsheet and is in fluidcommunication therewith. The topsheet transfers the acquired fluid tothis primary distribution layer for ultimate distribution to the storagelayer. This transfer of fluid through the primary distribution layeroccurs not only in the thickness, but also along the length and widthdirections of the absorbent article.

Besides the primarily fluid distribution layer additional optionaldistribution layers might be present. For example the also optionalsecondary distribution layer typically underlies the primarydistribution layer and is in fluid communication therewith. The purposeof this secondary distribution layer is to readily acquire fluid fromthe primary distribution layer and transfer it rapidly to the underlyingstorage layer. This helps the fluid capacity of the underlying storagelayer to be fully utilized. The fluid distribution layers can becomprised of any material typical for such distribution layers. Inparticular fibrous layers maintain the capillaries between fibers evenwhen wet and are useful as distribution layers.

Positioned in fluid communication with, and typically underlying thetopsheet, or optional primary or secondary distribution layers ifpresent, is a fluid storage layer. The fluid storage layer is anessential element of the absorbent element herein able to ultimatelyacquire and retain body fluid.

The fluid storage layer comprises as an essential element a liquidabsorbent thermoplastic composition comprising a thermoplastic polymericbase material having particles of water-insoluble water swellableabsorbent material dispersed therein, said composition being configuredin a plurality of unattached spaced apart zones also called hereinstorage zones.

The liquid absorbent thermoplastic composition might be used for totallyor partially substituting conventional fibrous storage layer comprisingwater swellable absorbent material. In a preferred embodiment of thepresent invention the storage layer consists of the liquid absorbentthermoplastic composition described herein configured in plurality ofunattached spaced apart zones.

By ‘plurality’ it is meant two or more unattached zones. By ‘unattached’it is meant herein that adjacent zones are individualized and separatedfrom each other without any physical link. However it is understoodherein that although said zones of the absorbent element are separatepieces of material they are operably/functionally assembled together. Itis understood herein that said zones provide at least part or evenpreferably the whole liquid absorption and retention capacity of theabsorbent element. Said zones that serve the function of absorbing andretaining the liquid, particularly body fluid, called herein also‘storage zones’, are delimited per regions located and extending betweenimmediately adjacent unattached spaced apart storage zones, said regionsare free of said liquid absorbent thermoplastic composition and arecalled herein the ‘liquid transport regions’. Said liquid transportregions help to more effectively and more rapidly distribute liquid,particularly body fluids, to the storage zones. Indeed when some storagezones are more wetted than other storage zones, e.g. the storage zoneslocated at entry point of fluid discharge versus more remote storagezones, the operability of the liquid transport regions can continue toprovide substantially unrestricted flow paths through the more wettedzones to the less wetted zones of the storage layer.

For example in typical absorbent articles body fluids primarily enterthe absorbent element, namely the storage layer, at the target sectionof the absorbent article, and the storage zones in the target sectioncan become wetted and even saturated prior to wetting and saturating thestorage zones in sections of the absorbent element/storage layer thatare relatively more remote from the target section. With thedistinctive, controlled preservation of liquid transport regions,however, fluid can readily flow around and past the more wetted andswollen storage zones to reach the more remote, less wetted zones. As aresult the complete absorbent capacity of substantially the entirestorage layer can be more effectively used. The invention canadvantageously provide a storage layer wherein the swelling of thestorage zones in the target section of the article does not inhibit theflow of fluid to the storage zones outside the target section.

Also advantageously the wicking speed upon subsequent fluid loading isequal or even faster than upon first body fluid discharge, resulting inimproved fluid acquisition and reduced rewetting occurrence. Without tobe bound by any theory, it is speculated that this is most likely due tothe fact that upon first contact with fluid the hydrophilicity of theoverall absorbent element comprising the storage layer and optionalfluid acquisition layer is enhanced, thereby enhancing the fluidhandling properties of the absorbent element upon subsequent body fluiddischarge.

The plurality of unattached spaced apart zones might be configured inany size as well as any type of shape and be provided via predeterminedor random application methods on a substrate in the article. The zonesmight take any type of geometrical form being regular or irregular inshape, including but not limited to lines/channels or stripes beingrectilinear or curved, dots, circles, squares, rectangles, triangles,lozenges, spirals and any combination thereof.

Preferably each of the unattached spaced apart storage zones can beconfigured to extend substantially continuously over an area of not lessthan 0.001 cm², preferably from 0.01 to 50 cm², more preferably from 0.5to 20 cm², even more preferably from 1 to 10 cm² and most preferablyfrom 2 to 5 cm² to provide storages zones having desiredcharacteristics.

In addition the overall system of storage zones can be positioned andarranged in desired patterns to provide a selected operable zones arraycomposed of the cooperating individual unattached spaced apart storagezones. The zones array, in one aspect of the present invention, canprovide a pattern size having total surface area extend of not less than1 cm², preferably from 1 to 200 cm², more preferably from 10 to 100 cm²,and most preferably from 20 to 75 cm². By ‘pattern size’ it is meantherein total surface area covered per all unattached spaced apart zoneswithout considering the interstitial area between said zones (alsocalled herein the transport regions).

In particular aspects of the invention, there is a discrete separationdistance between adjacent individual/unattached spaced apart zones. Thezones spacing distance is at least 0.1 mm, preferably is from 0.5 to 10mm, more preferably from 1 to 5 mm and most preferably from 1.2 to 3 mmto provide desired performance. If the separation distance betweenindividual storage zones is too small, the fluid may not be able to movealong and across the surfaces of the spaced apart zones of the storagelayer at a sufficiently rapid rate. If the separation distance betweenindividual storage zones is too big, the fluid may have the tendency tobe localized and distributed between the spaced apart zones, withoutbeing effectively absorbed per said zones, thereby saturating theabsorption capacity of the storage layer. Subsequent loading of fluidmight not be absorbed/retained as effectively as the storage layer isalready saturated. The whole absorbent capacity of the spaced apartzones might not be as effectively used.

Preferable pattern is such that the storage zones form continuous ordiscontinuous substantially parallel channels or stripes along thelongitudinal axis (MD direction) of the article. Such parallel stripesguide the fluid transport to the elongated direction of the stripes.Such pattern is particularly advantageous as it contributes most indelivering optimum properties in respect to fluid distribution/wickingproperties and hence overall fluid handling properties resulting inreduced rewet as well as enhanced flexibility to the article especiallyalong transverse axis (CD direction).

A particularly preferred pattern is illustrated in FIG. 1. FIG. 1 showsa pantyliner with a topsheet and backsheet being coextensive with eachother and being attached to each other along the outer edge of thepantyliner per heat bonding C. This pantyliner comprises a storage layerwith storage zones A that take the form of stripes delimiting liquidtransport regions B. The width of the stripe ‘a’ can vary as desired. InFIG. 1 the width ‘a’ is about 2 mm and the distance separating twoadjacent stripes ‘b’ is about 2 mm. FIG. 2 is a cross section of thepantiliner of FIG. 1 taken trough line D-D′, said liner comprises atopsheet (1), an adhesive layer (2) for adhering the topsheet to theunderlying fluid distribution layer (3), a storage layer (4), abacksheet (5) and adhesive layer (6) for adhering the backsheet (5) ofthe liner to a release liner (7). FIGS. 3 to 9 illustrate otherpantyliners according to the present invention with alternative patternof the plurality of spaced apart zones.

The use of such liquid absorbent thermoplastic composition configured ina plurality of spaced apart zones in the storage layer of the absorbentelement of the absorbent articles herein provides outstanding liquidabsorption capacity and liquid handling properties. More particularlydue to capillary effects enhanced liquid distribution is obtained andthe occurrence of gel blocking effect is reduced, resulting in enhancedliquid acquisition and retention with reduced soilage occurrence,especially when submitted to additional body fluid discharge uponprolonged wearing time. This results in reduced rewetting and enhanceddryness performance and hence improved overall comfort. All thesebenefits are obtained while not compromising on thinness and flexibilityof the whole absorbent article, but even improving said characteristics.

Advantageously the thermoplastic composition also serves the purpose offastening adhesive for attaching layers of the absorbent articlestogether, e.g., the backsheet to which the composition is typicallyadhered to, the topsheet or another layer if present like optional fluiddistribution layer or optimal fibrous layer.

In one embodiment herein in order to realize the benefits of the presentinvention the storage layer comprises a liquid absorbent thermoplasticcomposition having a total absorption capacity towards saline solutionof at least 2 grams per gram. Preferably the total absorption capacityof the composition towards saline solution is at least 5 g/g, morepreferably at least 15 g/g and most preferably at least 20 g/g. Thetotal absorption capacity of the composition used herein is determinedin test mentioned hereinafter.

The articles of the present invention have a total liquid absorptioncapacity great enough to absorb small vaginal discharge during nonmenstruation of the wearer or even medium to high menstrual flow. In apreferred embodiment herein the absorbent element is such as the totalliquid absorption capacity of the entire article is of at least 1 gram,preferably at least 2 to 80 grams, more preferably from 4 to 40 gramsand most preferably from 6 to 30 grams when measured according to thedunk absorption capacity test described herein after.

Typically the storage layer provides more than 80% of the totalabsorption capacity of the article, preferably more than 90% and mostpreferably from 90% to 100%.

In one embodiment herein the absorbent element comprises the liquidabsorbent thermoplastic composition described herein at a percent byweight of the total weight of the absorbent element of at least 15%,preferably from 20% to 100%, more preferably from 30% to 90%, even morepreferably from 45% to 85% and most preferably from 55% to 80%.

Preferably the liquid absorbent thermoplastic composition represents atleast 1% by weight of the total weight of the absorbent article,preferably from 5% to 90%, more preferably from 10% to 70%, even morepreferably from 15% to 50% and most preferably from 20% to 40%.

The storage layer comprises particles of water-insoluble water swellableabsorbent material dispersed homogeneously or non-homogeneously in athermoplastic polymeric base material, as the suitable carrier.

Water-insoluble but water-swellable absorbent materials or absorbentgelling materials are usually referred to as “hydrogels”, “superabsorbent”, “absorbent gelling” materials. Absorbent gelling materialsare those materials that, upon contact with aqueous fluids, especiallyaqueous body fluids, imbibes such fluids and thus form hydrogels. Theseabsorbent gelling materials are typically capable of absorbing largequantities of aqueous body fluids, and are further capable of retainingsuch absorbed fluids under moderate pressures. These absorbent gellingmaterials are typically in the form of discrete, non fibrous particles,even if super absorbent in fiber form are known.

Any commercially available super absorbent material in particle form issuitable for the present invention. Suitable absorbent gelling materialsfor use herein will most often comprise a substantially water-insoluble,slightly crosslinked, partially or fully neutralized, polymeric gellingmaterial. This material forms a hydrogel upon contact with water. Suchpolymer materials can be prepared from polymerizable, unsaturated,acid-containing monomers. Suitable unsaturated acidic monomers for usein preparing the polymeric absorbent gelling material used in thisinvention include those listed in U.S. Pat. No. 4,654,039 and reissuedas RE 32,649. Preferred monomers include acrylic acid, methacrylic acid,and 2-acrylamido-2-methyl propane sulfonic acid. Acrylic acid itself isespecially preferred for preparation of the polymeric gelling material.The polymeric component formed from the unsaturated, acid-containingmonomers can be grafted onto other types of polymer moieties such asstarch or cellulose. Polyacrylate grafted starch materials of this typeare especially preferred. Preferred polymeric absorbent gellingmaterials that can be prepared from conventional types of monomersinclude hydrolyzed acrylonitrile grafted starch, polyacrylate graftedstarch, polyacrylates, maleic anhydride-based copolymers andcombinations thereof. Especially preferred are the polyacrylates andpolyacrylate grafted starch, but other absorbent substances in particleform such as inorganic materials (MgSO₄, CaCl₂, silicas, zeolites, etc.)or absorbing polymers (i.e. chitin derivatives such as, for example,chitosan) can be used alone but, preferably, blended with the abovesuper absorbent polymers.

It is preferable that the particle size of the absorbent material usedherein in dry state is below 150 micrometers, more preferably below 50micrometers and most preferably from 40 to 10 micrometers. Smallparticle size are preferred herein as this results in optimumperformance and processability for adhering the thermoplasticcomposition to the desired substrate. “Particle size” as used hereinmeans the weighted average of the smallest dimension of the individualparticles. Highly preferred water insoluble water swellable materialsfor use herein have a substantially angle-lacking shape and preferablyhave a spherical shape. Suitable commercially available absorbentgelling material is for example Aquakeep® 10SH-NF, available fromSumitomo Seika, having an average particle size of between 20 μm and 30μm.

It is preferable that the water insoluble water swellable absorbentmaterial is present in an amount from 1% to 95%, preferably from 10% to90%, more preferably from 30% to 70% and most preferably from 40% to 60%by weight of the total liquid absorbent thermoplastic composition.

The liquid absorbent thermoplastic composition for use herein besidesthe absorbent material further comprises as an essential element apolymeric base material typically at a level from 5% to 99%, preferably10% to 90%, more preferably from 30% to 70%, most preferably from 40% to60% by weight of the liquid absorbent thermoplastic composition.

Any polymeric base material known to the skilled person andconventionally used in the construction of absorbent articles, such asfeminine care absorbent articles (e.g. sanitary napkins, panty liners orincontinence articles) or baby care absorbent articles (e.g. diapers)can be used herein. The polymeric base materials for use herein comprisethermoplastic polymers as an essential element. Thermoplastic polymer ormixtures of polymers are present in amounts typically ranging from about5% to 99%, preferably 10% to 90%, more preferably from 30% to 70%, mostpreferably from 40% to 60% with respect to the total weight of thethermoplastic polymeric base material.

A variety of different thermoplastic polymers are suitable for useherein. Exemplary thermoplastic polymers include but are not limited toblock copolymers, amorphous and crystalline polyolefins includinghomogeneous and substantially linear ethylene/alpha-olefininterpolymers, interpolymers of ethylene such as ethylene-vinyl-acetate(EVA), ethylene-methyl-acrylate (EMA) and ethylene n-butyl acrylate(EnBa) and mixtures thereof. The group of block copolymers includeslinear copolymers of the triblock A-B-A or the diblock A-B type, orradial co-polymer structures having the formula (A-B)_(x). The A blocksare non-elastic polymer blocks, typically polyvinylarene blocks, the Bblocks are unsaturated conjugated dienes, such as poly(monoalkenyl)blocks, or hydrogenated versions thereof, x denotes the number ofpolymeric arms, and x is an integer greater than or equal to one.Suitable block A polyvinylarenes include, but are not limited topolystyrene, polyalpha-methylstyrene, polyvinyltoluene, and combinationsthereof. Suitable block B poly(monoalkenyl) blocks include, but are notlimited to conjugated diene elastomers such as for example polybutadieneor polyisoprene or hydrogenated elastomers such as ethylene butylene orethylene propylene or polyisobutylene, or combinations thereof.Commercial examples of these types of block copolymers includeEuroprene™ Sol T from EniChem, Kraton™ elastomers from Shell ChemicalCompany, Vector™ elastomers from Dexco, Solprene™ from EnichemElastomers and Stereon™ from Firestone Tire & Rubber Co.

Amorphous polyolefins or amorphous polyalphaolefins (APAO) arehomopolymers, copolymers, and terpolymers of C₂-C₈ alphaolefins. Thesematerials are typically polymerised by means of processes, which employZiegler-Natta catalysts resulting in a relatively broad molecular weightdistribution. Commercially available amorphous polyalphaolefins includeRextac™ and REXFlex™ propylene based homopolymers, ethylene-propylenecopolymers and butene-propylene copolymers available from Rexene(Dallas, Tex.) as well as Vestoplast alpha-olefin copolymers availablefrom Huls (Piscataway, N.J.).

Metallocene polyolefins are homogeneous linear and substantially linearethylene polymers prepared using single-site or metallocene catalysts.Homogeneous ethylene polymers are characterized as having a narrowmolecular weight distribution and a uniform short-chain branchingdistribution. In the case of substantially linear ethylene polymers,such homogeneous ethylene polymers are further characterized as havinglong chain branching. Substantially linear ethylene polymers arecommercially available from The Dow Chemical Company as Affinity™polyolefin plastomers, which are produced using Dow's Insite™technology, whereas homogeneous linear ethylene polymers are availablefrom Exxon Chemical Company under the tradename Exact™. Homogeneouslinear and substantially linear ethylene polymers having a relativelylow density, ranging from about 0.855 to about 0.885, and a relativelylow melt index, for example less than about 50 g/10 min are mostpreferred, particularly for creating elastomeric fibers, films andadhesive compositions that swell upon exposure to water.

The term ‘interpolymer’ is used herein to indicate a copolymer,terpolymer, or higher order polymer. That is, at least one othercomonomer is polymerized with ethylene to make the interpolymer.Interpolymers of ethylene are those polymers having at least onecomonomer selected from the group consisting of vinyl esters of asaturated carboxylic acid wherein the acid moiety has up to 4 carbonatoms, unsaturated mono- or dicarboxylic acids of 3 to 5 carbon atoms, asalt of the unsaturated acid, esters of the unsaturated acid derivedfrom an alcohol having 1 to 8 carbon atoms, and mixtures thereof.

If employed uncompounded, the ethylene to unsaturated carboxyliccomonomer weight ratio is preferably greater than about 3:1, morepreferably about 2:1. Hence, the comonomer concentration is preferablygreater than 30 wt-%, more preferably greater than 33 wt-% and mostpreferably greater than 35 wt-%, with respect to the total weight of theethylene interpolymer. The melt index of the interpolymers of ethylenemay range from about 50 to about 2000, preferably from about 100 to1500, more preferably from about 200 to 1200, and most preferably fromabout 400 to 1200 g/10 min. When employing a polymer having too low of amelt index uncompounded, the strength of the polymer tends to constrainthe swelling of the particles of super absorbent material.

Suitable ethylene/unsaturated carboxylic acid, salt and esterinterpolymers include ethylene/vinyl acetate (EVA) ethylene/acrylic acid(EEA) and its ionomers; ethylene/methacrylic acid and its ionomers;ethylene/methyl acrylate (EMA); ethylene/ethyl acrylate;ethylene/n-butyl acrylate (EnBA); as well as various derivatives thereofthat incorporate two or more comonomers.

Other suitable thermoplastic polymers that may be employed includepolylactide, caprolactone polymers, and poly(hydroxy-butyrate/hydroxyvalerate), certain polyvinyl alcohols,biodegradable copolyesters such as Eastman Copolyester 14766 (Eastman),linear saturated polyesters such as Dynapol or Dynacoll polymers fromHuls, poly (ethylene oxide) polyether amide and polyester ether blockcopolymers available from Atochem (Pebax™) or Hoechst Celanese(Rite-flex™) respectively, and polyamide polymers such as thoseavailable from Union Camp (Unirez™) or Huls (Vestamelt™) or EMS-Chemie(Griltex™). Other suitable thermoplastic polymers are e.g.polyurethanes, poly-ether-amides block copolymers, polyethylene-acrylicacid and polyethylene-methacrylic acid copolymers, polyethylene oxideand its copolymers, ethylene acrylic esters and ethylene methacrylicesters copolymers, polylactide and copolymers, polyamides, polyestersand copolyesters, polyester block copolymers, sulfonated polyesters,poly-ether-ester block copolymers, poly-ether-ester-amide blockcopolymers, ionomers, polyethylene-vinyl acetate with a vinyl acetatecontent of at least 28% by weight, polyvinyl alcohol and its copolymers,polyvinyl ethers and their copolymers, poly-2-ethyl-oxazoline andderivatives, polyvinyl pyrrolidone and its copolymers, thermoplasticcellulose derivatives, poly-caprolactone and copolymers, poly glycolide,polyglycolic acid and copolymers, polylactic acid and copolymers,polyureas, polyethylene, polypropylene, or mixtures thereof.

Particularly suitable preferred thermoplastic polymers are selected fromthermoplastic poly-ether-amide block copolymers (e.g. Pebax™),thermoplastic poly-ether-ester-amide block copolymers, thermoplasticpolyester block copolymers (e.g. Hytrel™), thermoplastic polyurethanes(e.g. Estane™), or mixtures thereof.

The polymeric base material for use herein preferably further comprisesuitable compatible plasticizers. Plasticizers or mixture thereof arepreferably present in amounts ranging from about 5% to 90%, preferably10% to 80%, more preferably from 15% to 70% and most preferably from 30%to 65%, by weight, with respect to the total weight of the thermoplasticpolymeric base material. Suitable ‘plasticizers’ for use hereingenerally will include any conventional plasticizers which decreasehardness and modulus, enhance pressure sensitive tack and reduce meltand solution viscosity. It is preferred that the plasticizer be watersoluble or water dispersible or alternatively be a wax-like substancesuch as polyethylene or polypropylene glycol, glycerin, glycerol and itsesters, butylene glycol or sorbitol. Other plasticizers suitable for useherein are esters of sucrose; phthalate plasticizers such as dioctylphthalate and butyl benzyl phthalate (e.g., Santicizer 160 fromMonsanto); benzoate plasticizers such as 1,4-cyclohexane dimethanoldibenzoate (e.g., Benzoflez 352 from Velsicol), diethyleneglycol/dipropylene glycol dibenzoate (e.g., Benzoflez 50 from Velsicol),and diethylene glycol dibenzoate where the mole fraction of hydroxylgroups which have been esterified ranges from 0.5 to 0.95 (e.g.,Benzoflex 2-45 High Hydroxyl also from Velsicol); phosphite plasticizerssuch as t-butyl diphenyl phosphate (e.g., Santicizer 154 from Monsanto);adipates; sebacates; epoxidized vegetal oils; polymerised vegetal oils;polyols; phthalates; liquid polyesters such as Dynacol 720 from Huls;glycolates; p-toluene sulfonamide and derivatives; glycols andpolyglycols and their derivatives; sorbitan esters; phosphates;monocarboxylic fatty acids (C₈-C₂₂) and their derivatives; liquid rosinderivatives having Ring and Ball hydrocarbon oils which are low inaromatic content and which are paraffinic or naphthenic in character andmixtures thereof. Plasticizer oils are preferably low in volatility,transparent and have as little color and odor as possible. An example ofa preferred plasticizer is Carbowax™ polyethylene glycol from UnionCarbide. The use of plasticizers also contemplates the use of olefinoligomers, low molecular weight polymers, vegetable oils and theirderivatives and similar plasticizing liquids.

Particularly preferred plasticizers to be used herein are hydrophilicplasticizers such as acids, esters, amides, alcohols, polyalcohols, ormixtures thereof, among which even more preferred are citric acidesters, tartaric acid esters, glycerol and its esters, sorbitol,glycolates, and mixtures thereof, as disclosed in our application WO99/64505. Said preferred hydrophilic plasticizers have a particularlyhigh polar character and provide the further advantage that they do notimpair, and possibly can even enhance, the moisture vapor permeabilityof the resulting layer formed from the polymeric base material and thusthe liquid absorbent thermoplastic composition used herein comprisingsaid preferred plasticizer or blend of plasticizers, when compared to acorresponding layer formed from an liquid absorbent thermoplasticcomposition comprising the same components, but without such aplasticizer or plasticizers.

These particularly preferred hydrophilic plasticizer or blend ofhydrophilic plasticizers can of course also adjust the viscosity of thepolymeric base material and thus of the liquid absorbent thermoplasticcomposition to desirable values in order to help processable whenadhering said composition onto a substrate.

According to a further even more preferred embodiment of the presentinvention, for avoiding migration of the plasticizer or blend ofplasticizers from the matrix of thermoplastic polymeric base material itis preferable that the molecular weight (MW) of the selected plasticiseror plasticisers be greater than 300, preferably greater than 1000, andmore preferably greater than 3000. Plasticisers having a MW of at least6000 work particularly well.

As a matter of fact absorbent articles are assembled by and containconventional hydrophobic hot melt adhesive which can interact with theabsorbent material of the present invention and particularly with itshydrophilic plasticizer giving rise to a degradation of the adhesivecharacteristics of the conventional hot melt adhesive. For example, asanitary napkin or a panty liner is generally made of a liquid permeabletopsheet, of a liquid impermeable backsheet, and of an fibrous absorbentcore there between. Generally the outside of the backsheet is providedwith stripes of conventional hot melt pressure sensitive adhesive forfastening the absorbent article to the user's panty. If saidconventional absorbent core is substituted in total or in part by aabsorbent element made of the absorbent thermoplastic compositiondescribed herein, for example coated onto the inner surface of thebacksheet, the inventors have surprisingly found that if the hydrophilicplasticiser or the blend of hydrophilic plasticisers are selected fromthose having a molecular weight (MW) greater than 300, preferablygreater than 1000, more preferably greater than 3000, there is nointerference with the adhesive for fastening the absorbent article, i.e.no peel reduction of said adhesive is experienced, while usinghydrophilic plasticizers of lower molecular weight a significantreduction of adhesive peel is experienced, presumably due to plasticisermigration out of the liquid absorbing thermoplastic composition.

Most preferably, plasticisers having the preferred molecular weight asexplained above can be selected from the group consisting of glycerolesters, sucrose esters, sorbitol, epoxidized vegetal oils, polymerisedvegetal oils, polyalcohols, polyols, liquid polyesters, p-toluenesulfonamide and derivatives, polyglycols and their derivatives,monocarboxylic fatty acids (C₈-C₂₂) and their derivatives, and mixturesthereof, wherein polyglycols and their derivatives are particularlypreferred (i.e. polyethylene glycols and polypropylene glycols).

The polymeric base material for use in the liquid absorbentthermoplastic composition herein optionally also comprises tackifyingresins. Tackifying resins are preferably present in amounts ranging fromabout 0% to 100%, preferably 1% to 30%, more preferably from 5% to 20%and most preferably from 8% to 12% by weight of total weight of thethermoplastic polymeric base material. As used herein, the term‘tackifying resin’ means any of the liquid absorbent thermoplasticcompositions described below that are useful to impart tack to thepolymeric base material. ASTM D1878-61T defines tack as “the property ofa material which enables it to form a bond of measurable strengthimmediately on contact with another surface”. Tackifying resins compriseresins derived from renewable resources such as rosin derivativesincluding wood rosin, tall oil and gum rosin as well as rosin esters,natural and synthetic terpenes and derivatives of such. Aliphatic,aromatic or mixed aliphaticaromatic petroleum based tackifiers are alsouseful in the invention. Representative examples of useful hydrocarbonresins include alpha-methyl styrene resins, branched and unbranched C₅resins, C₉ resins and C₁₀ resins, as well as styrenic and hydrogenatedmodifications of such. Tackifying resins range from being a liquid at37° C. to having a ring and ball softening point of about 135° C.Suitable tackifying resins for use herein include natural and modifiedresins; glycerol and pentaerythritol esters of natural and modifiedresins; polyterpene resins; copolymers and terpolymers of naturalterpenes; phenolic modified terpene resins and the hydrogenatedderivatives thereof; aliphatic petroleum resins and the hydrogenatedderivatives thereof; aromatic petroleum resin and the hydrogenatedderivatives thereof; and aliphatic or aromatic petroleum resins and thehydrogenated derivatives thereof, and combinations thereof. Commercialexamples of these types of resins include Foral™ hydrogenated rosinester, Staybelite™ hydrogenated modified rosin, Polypale™ polymerizedrosin, Permalyn™ rosin ester, Pentalyn™ rosin ester, Adtac™ oil extendedhydrocarbon resin, Piccopale™ aromatic hydrocarbon, Piccotac™, Hercotac™aromatic modified aliphatic hydrocarbon, Regalrez™ cycloaliphaticresins, or Piccolyte™ from Hercules, Eselementz™ from Exxon Chemicalaliphatic hydrocarbon and cycloaliphatic resins, Wingtack™ from GoodyearTire & Rubber Co. synthetic polyterpene resins including aromaticmodified versions, Arkon™ partially and fully hydrogenated aromaticresins from Arakawa Chemicals, Zonatac™ styrenated terpene resin,Zonarez™ rosin ester and Zonester™ rosin ester from Arizona Chemical andNevtac™ aromatic modified aliphatic hydrocarbon from Neville ChemicalCompany.

The polymeric base material for use in the liquid absorbentthermoplastic composition herein optionally also comprisesanti-oxidants. Antioxidant are typically present in amounts ranging fromabout 0.1% to 10%, preferably 0.2% to 5%, more preferably from 0.5% to2%, most preferably from 0.75% to 1.5% by weight of total weight of thepolymeric base material. Suitable ‘anti-oxidants’ for use herein includeany conventional anti-oxidants, and are preferably hindered phenols suchas for example Ethanox 330™1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzenewhich is commercially available from the Ethyl Corporation. Otherexamples for suitable anti-oxidants are hindered phenolics (e.g.,Irganox 1010, Irganox 1076).

The polymeric base material for use in the liquid absorbentthermoplastic composition herein optionally also comprises surfactants.Suitable ‘surfactants’ for use herein are additives that reduce thesurface tension and/or contact angle of the polymeric base material.Surfactants are typically present in amounts ranging from about 0 wt-%to about 25 wt-% and preferably from about 5 wt-% to about 15 wt %, withrespect to the total weight of the thermoplastic polymeric basematerial. Suitable surfactants include nonionic, anionic, and siliconesurfactants. Exemplary nonionic surfactants are: Ethoxylates of (i)C₁-C₁₈, preferred C₈-C₉ alkyl or dialkyl phenols, such as those soldunder the tradenames Macol DNP-10, available from PPG Industries,Gurnee, Ill., a 10 mole ethoxylate of dinonyl phenol, and Triton X-100,available from Union Carbide, a 10 mole ethoxylate of octyl phenol; (ii)alkyl C₈-C₆₀ monoalcohols, such as those sold under the tradenamesSurfonic L-12-8, an 8 mole ethoxylate of dodecanol, available fromHuntsman Chemical Co., and Unithox 480, a 38 mole ethoxylate crystallinesurfactant available from Petrolite Specialty Polymers Group, Tulsa,Okla.; and (iii) propylene oxide polymers, such as those sold under thetradename Pluronic, which are ethylene oxide/propylene oxide blockcopolymers having a Mn of 200 to 3000, available from BASF; andbenzoates formed by partial condensation of benzoic acid withhydrophilic di or mono-ols having less than 1000 Mn, such as the productof condensing about three equivalents of benzoic acid with fourequivalent of diethylene glycol, commercially available as XP 1010 fromVelsicol Chemical. A preferred nonionic surfactant blend is Atmer 685,available from ICI Surfactants (Wilmington, Del.). Suitable anionicsurfactants are: C₈-C₆₀ alkyl ethoxylate sulfonates,(CH₃—(CH₂)₁₁₋₁₄—(O—CH₂—CH₂)₃—SO₃ ⁻Na⁺, such as, Avenel S30, availablefrom PPG Industries; alkyl C₈-C₆₀ sulfonates, such as, Rhodapon UB(C₁₂—SO₃ ⁻Na⁺) available from Rhone Poulenc; and alkyl/aromaticsulfonates, such as those sold under the tradename Calsoft. Suitablesilicone surfactants are ethoxylates or propoxylates of polydimethylsiloxane, having a number average molecular weight of 500 to 10,000,preferably 600 to 6000, such as are sold under the tradenames SilwetL-77, L-7605, and L-7500 availablefrom OSi Specialties, Danbury, Conn.;and product 193 from Dow Corning. The preferred surfactants are thosewith lower molecular weights because these have increased compatibilityin the polymeric base material. The maximum acceptable molecular weightdepends on the type of surfactant and the other ingredients in thepolymeric base material and thus the liquid absorbent thermoplasticcomposition.

Other optional components of the polymeric base material for use hereininclude anti-ultraviolets, dyes, antibacterials, odour adsorbingmaterials, perfumes, pharmaceuticals, and mixtures thereof, which may bepresent within the liquid absorbent thermoplastic compositions at alevel of up to 20% by weight of the composition.

The liquid absorbent thermoplastic composition suitable for use hereinis preferably a hot-melt adhesive, i.e. the polymeric base materialcomprises a hot-melt adhesive, which is capable of absorbing aqueousliquids. Such preferred liquid absorbent thermoplastic compositionscomprise (by weight):

a) from about 5% to about 99% of a polymeric base material, comprising

-   -   a′) from about 10% to about 50% of a block copolymer,    -   a″) from about 0% to about 50% of a tackifying resin;    -   a′″) from about 10% to about 80% plasticizer,    -   a″″) from about 0% to about 2.0% antioxidant; and        b) from about 1% to about 95% of particles of water insoluble        water swellable absorbent material.

Highly preferred thermoplastic polymeric base materials for use in theliquid absorbent thermoplastic compositions described herein before arethose having a water absorption capacity of at least greater than 30%,preferably greater than 40%, more preferably greater than 60% and mostpreferably greater than 90%, when measured according to the WaterAbsorption Test described herein in accordance with ASTM D 570-81, on afilm 200 μm thick. The intrinsic absorbency of the polymeric basematerial/matrix allows for a more effective diffusion of the body fluidwithin the matrix and, consequently, for a better spreading of the bodyfluid which can reach a greater number of absorbent material particleswhich in turn give rise to a better utilization of the absorbentmaterial.

Highly preferred liquid absorbent thermoplastic compositions describedherein before are those showing good integrity in wet state and hencehaving a tensile strength in wet state which is at least 20%, preferablyat least 40%, and more preferably 60% of the tensile strength of saidcomposition in dry state. Said tensile strengths are evaluated accordingto the Tensile Strength Test described herein. It should be appreciatedthat by selecting a thermoplastic base material, in the liquid absorbentthermoplastic composition herein having a higher value of waterabsorption, the absorbent composition will have better liquidabsorption/handling characteristics, while not compromising on tensilestrength in wet state. Indeed such absorbent composition will remainsubstantially intact and have sufficient tensile strength for itsintended use, also upon liquid absorption.

Indeed the highly preferred liquid absorbent thermoplastic compositionsfor use herein offer improved mechanical and absorbent properties.Without to be bound by theory it is believed that the intrinsicabsorbency of the matrix allows the body fluid to be acquired anddiffused within the matrix thus permitting fluid contact with theabsorbent material contained in the matrix and their swelling, withoutthe necessity of having a matrix of low cohesive strength but with amatrix which remains substantially intact and having sufficient strengthupon fluid absorption.

The absorbent in particle form or mixture thereof are blended with thepolymeric base material in any known manner to provide the liquidabsorbent thermoplastic composition for use herein. For example, byfirst melting the thermoplastic polymeric base material and then byadding and mixing the required amount of absorbent material particles.Suitable adhesive processing equipments can be used such as a melt mixeror extruder. Preferably the liquid absorbing thermoplastic compositionsfor use herein are formulated to have hot melt characteristics so thatthey can be applied utilizing any know method used for applying hot meltadhesives.

At least at the coating temperature, since the liquid absorbentthermoplastic composition comprises thermoplastic polymeric basematerials, it can exhibit adhesive properties on a supportive substratein order to form a composite structure such that no additional adhesiveis required to achieve a permanent attachment between the absorbentelement provided partially or preferably completely per the liquidabsorbent thermoplastic composition, and the substrate. However, whilehot melt techniques are preferred, any other known method for processingthermoplastic compositions can be used for processing the absorbentcompositions in any known form/pattern. Also, any known method forspraying, printing, dotting, coating or foaming thermoplasticcompositions can be used as well as extrusion, lamination processes.

Particularly suitable methods for applying the liquid absorbentthermoplastic composition to a substrate is per gravure printing or slotcoating. Both methods are particularly suitable for discontinuousapplication of the thermoplastic composition described herein onto asubstrate. Gravure print unit or slot coater apply the thermoplasticcomposition in the desired pattern onto a substrate.

Because the absorbent composition is thermoplastic, it allows for hotmelt technique applications which in turn increase the versatility ofits application in different form covering several distinct parts ofwhole surface of the layer substrate to which is applied to therebyproviding the so called storage zones, typically the topsheet orbacksheet or any intermediate layer directly adjacent the compositionand interposed therebetween any of the outer surface of the article,i.e. topsheet and/or backsheet. The liquid absorbent composition can beprovided covering discontinuously the article across its entire surfaceor it can cover only a region thereof, for example the central region ofan article where body fluid is discharged in use. The total area of asurface onto which the liquid absorbent thermoplastic composition isapplied to (preferably backsheet or any intermediate layers like fluiddistribution layer if present or fibrous underlying layer if present)defines the actual absorbent surface of said composition in theabsorbent article.

In one embodiment the totality of the plurality of unattached spacedapart zones represent as a minimum 8% of the total surface area of theabsorbent article, when considering the plane surface occupied per thetotality of said zones in respect to total plane surface area of thetotal article. Preferably the totality of the plurality of unattachedspaced apart zones occupy a surface area which is from 15% to 90%, morepreferably from 20% to 50% and most preferably from 25% to 40% of thetotal surface area of absorbent article.

An optional component for inclusion in the absorbent element accordingto the present invention is a fibrous layer adjacent to, and typicallyunderlying the storage layer. If present this layer provides a substrateon which to deposit the liquid absorbent thermoplastic compositionduring manufacture of the absorbent element. If present such a layertypically provides some additional fluid-handling capabilities such asrapid wicking of fluid along the length of the absorbent article.Typically such a layer might be present if high capacity is desired likein the case of sanitary napkins for menstruation use. Such fibrous layerbesides the transport regions is able to create additional void volumeto handle and store temporary body fluids before being absorbed by theplurality of the spaced apart storage zones. In the case of liners fordaily usage, where the total capacity and fluid handling propertiesneeds are less demanding such layer is typically absent from theabsorbent element and the thermoplastic composition is preferablyadhered directly to the backsheet. Any material known to those skilledin the art might be used herein for the fibrous layer including but notlimited to fibrous nowoven or woven material made of natural orsynthetic fibers like polyolefines or cellulose.

Topsheet

The topsheet is compliant, soft feeling, and non-irritating to thewearer's skin. The topsheet also can be elastically stretchable in oneor two directions. Further, the topsheet is preferably liquid perviouspermitting body fluids to readily penetrate through its thickness.

A suitable topsheet can be manufactured from a wide range of materialssuch as woven and nonwoven materials; polymeric materials such asapertured formed thermoplastic films, apertured plastic films, andhydroformed thermoplastic films; porous foams; reticulated foams;reticulated thermoplastic films; and thermoplastic scrims. Suitablewoven and nonwoven materials can be comprised of natural fibers (e.g.,wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such aspolyester, polypropylene, or polyethylene fibers) or from a combinationof natural and synthetic fibers. Suitable nonwoven materials/layersinclude fibrous nonwoven materials/layers formed by a carding process ora spunbond process or meltblown process whereby molten polymericmaterial is extruded through a die, attenuated to lengthen the extrudedpolymer into fibers and decrease the diameter thereof and issubsequently deposited on a forming surface. Methods of forming suchnonwoven materials/layers are known to those skilled in the art.Polymeric materials suitable for use in forming such fibrous nonwovenmaterials/layers include polyolefins such as polyethylene andpolypropylene, polyesters, nylons, ethylene vinyl acetate, ethylenemethacrylate, copolymers of the above materials, block copolymers suchas A-B-A block copolymers of styrene and butadiene, and the like.

Apertured formed films are especially preferred for the topsheet becausethey are pervious to body exudates and yet non-absorbent and have areduced tendency to allow fluids to pass back through and rewet thewearer's skin. Thus, the surface of the formed film that is in contactwith the body remains dry, thereby reducing body soiling and creating amore comfortable feel for the wearer. Suitable formed films aredescribed in U.S. Pat. No. 3,929,135; U.S. Pat. No. 4,324,246; U.S. Pat.No. 4,342,314; U.S. Pat. No. 4,463,045; and U.S. Pat. No. 5,006,394.Particularly preferred microapertured formed film topsheets aredisclosed in U.S. Pat. No. 4,609,518 and U.S. Pat. No. 4,629,643. Apreferred topsheet for the present invention is the apertured formedfilm described in one or more of the above patents and marketed onsanitary napkins by The Procter & Gamble Company of Cincinnati, Ohio as“DRI-WEAVE.” The body surface of the formed film topsheet can behydrophilic so as to help liquid to transfer through the topsheet fasterthan if the body surface was not hydrophilic. In a preferred embodiment,surfactant is incorporated into the polymeric materials of the formedfilm topsheet such as is described in U.S. patent application Ser. No.07/794,745, filed on Nov. 19, 1991. Alternatively, the body surface ofthe topsheet can be made hydrophilic by treating it with a surfactantsuch as is described in the above referenced U.S. Pat. No. 4,950,254.

In yet an embodiment herein the topsheet is used together with an outerlayer being directed towards the wearer surface. Such an outer layer isdisposed onto the topsheet in a discontinuous way so that at least theregion where liquid is expected to be discharged onto the absorbentarticle is free of the outer layer. Indeed, it is particularly preferredthat the topsheet be a so-called hybrid topsheet in which the wearercontacting surface is provided in its longitudinal center by anapertured polymeric film or nonwoven while a region not including thecenter is provided with a non-woven such as e.g. the high loft non-wovenor other non-woven which does provide particularly skin friendliness.Such hybrid topsheets have been disclosed in EPA-523 683, EP-A-523 719,EP-A-612 233, or EP-A-766 953.

Backsheet

The backsheet prevents the liquids absorbed and contained in theabsorbent element from wetting articles that contact the absorbentarticle such as pants, pajamas and undergarments. The backsheet ispreferably impervious to liquids like body fluids and is preferablymanufactured from a thin plastic film, although other flexible liquidimpervious materials can also be used. The backsheet needs to becompliant and will readily conform to the general shape and contours ofthe human body. The backsheet also can have characteristics allowing itto elastically stretch in one or two directions.

The backsheet can comprise a woven or nonwoven material, polymeric filmssuch as thermoplastic films of polyethylene or polypropylene, orcomposite materials such as a film-coated nonwoven material.

Exemplary polyethylene films are manufactured by Clopay Corporation ofCincinnati, Ohio, under the designation P18-0401 and by EthylCorporation, Visqueen Division, of Terre Haute, Ind., under thedesignation XP-39385. The backsheet is preferably embossed and/or mattefinished to provide a more clothlike appearance.

The backsheet typically extends across the whole of the absorbentelement and can extend into and form part of or all of the preferredsideflaps, side wrapping elements or wings if such elements are present.

In addition to the prevention of liquid transport through the backsheet,the backsheet is preferably breathable. Hence the backsheet also permitsthe transfer of water vapor and preferably both water vapor and airthrough it and thus allows reduction of humid and occlusive environmenton the skin contacted with the article. Advantageously the articles ofthe present invention, provided with a breathable backsheet, exhibitoutstanding dry feeling both in dry and wet conditions and hence furtherenhanced comfort. Indeed the absorbent element according to the presentinvention comprising the liquid absorbent thermoplastic compositionconfigured in unattached spaced apart zones as described hereinsignificantly increases both the air and the water vapor permeability ofthe article during both dry and wet conditions. For example in wetcondition a recovering of more than 80% of the original air permeabilityhas been observed with articles according to the present invention(e.g., with the article exemplified in FIGS. 1 and 2, the recovering wasof about 90%). Indeed it is speculated that after fluid discharge thetransport regions transfer the fluid to the storages zones, therebymaintaining void space which results in reduction of the occlusioneffect that normally occurs with conventional core materials/design.

Suitable breathable backsheets for use herein include all breathablebacksheets known in the art. Suitable for use herein are single layerbreathable backsheets which are breathable and impervious to liquids ordual layer backsheet, which in combination provide both breathabilityand liquid imperviousness.

Suitable single layer breathable backsheets for use herein include thosedescribed for example in GB A 2184 389, GB A 2184 390, GB A 2184 391,U.S. Pat. No. 4,591,523, U.S. Pat. No. 3,989,867, U.S. Pat. No.3,156,242 and WO 97/24097.

Suitable apertured formed films include films which have discreteapertures which extend beyond the horizontal plane of the garment facingsurface of the layer towards the core thereby forming protuberances. Theprotuberances have an orifice located at their terminating ends.Preferably said protuberances are of a funnel shape, similar to thosedescribed in U.S. Pat. No. 3,929,135. Preferably said aperturedpreformed films are uni directional such that they have at leastsubstantially, if not complete one directional fluid transport towardsthe absorbent element. Suitable macroscopically expanded films for useherein include films as described in for example in U.S. Pat. No.637,819, U.S. Pat. No. 4,591,523, U.S. Pat. No. 4,637,819 and U.S. Pat.No. 4,591,523.

Suitable monolithic films include Hytrel™, available from DuPontCorporation, USA, and other such materials as described in Index 93Congress, Session 7A “Adding value to Nonwovens”, J-C. Cardinal and Y.Trouilhet, DuPont de Nemours International S.A., Switzerland.

Suitable breathable backsheets for use herein are made of a first and asecond layer. The first layer is positioned between the garment facingsurface of the absorbent element and the wearer facing surface of thesecond layer/outer layer. It is oriented such that it retards orprevents liquid from passing from the absorbent element towards theoutside while allowing free air flow and water vapor through it. Thesecond layer provides water vapor and air permeability so as to supportbreathability of the article. In addition to water vapor permeabilitythe air permeability is desirable in order to further improve thecomfort benefit from the breathability of the article. Such a firstlayer provides air and water vapor permeability by being apertured.Preferably this layer is made in accordance with the aforementioned U.S.Pat. No. 5,591,510 or PCT WO 97/03818, WO 97/03795. In particular, thislayer comprises a polymeric film having capillaries. Using a monolithicpolymer film as the material for the first layer provides water vaporpermeability even under stress conditions. While the apertures provideair permeability during “leakage safe” situations but close thecapillaries under stress conditions the monolithic material maintainswater vapor permeability in such a case. Preferred breathable monolithicfilm materials for use herein are those having a high vapor exchange.

In one embodiment herein the backsheet is made of a first layer of aresilient, three dimensional web which consists of a liquid imperviouspolymeric film having apertures forming capillaries which are notperpendicular to the plane of the film but are disposed at an angle ofless than 90° relative to the plane of the film, and a second breathablelayer (outer layer) of a porous web which is a fibrous nonwovencomposite web of a meltblown nonwoven layer made from synthetic fibershaving a basis weight of less than 28, preferably less than 13 g/m² andof a spunbonded nonwoven layer made from synthetic fibers.

The backsheet typically forms the garment facing surface on which thepanty fastening adhesive is placed. Panty-fastening-adhesives cancomprise any adhesive or glue used in the art for such purposes withpressure-sensitive adhesives being preferred.

According to the present invention the absorbent article may findutility as sanitary napkins, panty liners, adult incontinence products,nursing pads, baby diapers and the like. The present invention findsparticular susceptibility as sanitary napkins and panty liners. A newproduct design, which is a sub-form of a sanitary napkin or panty linerform, namely thong shaped sanitary napkins or panty liners, so calledthong liners, are included herein too.

Optionally, the absorbent articles of the present invention can compriseall those components typical for the intended product use. For exampleabsorbent articles can comprise components such as wings in order toimprove their positioning and soiling protection performance especiallytowards the rear end of the article. Such designs are shown for examplein EP 130 848 or EP 134 086, Thong liners with wings are shown in U.S.design 394,503, UK designs 2,076,491 and 2,087,071 as well asinternationally filed industrial model DM 045544, filed under the HagueAgreement, registered on Oct. 21, 1998.

Irrespective whether the wings are specially designed for thong linersor for conventional absorbent articles they can be provided as separatepieces and be attached to the thong liner or conventional pantiliners orsanitary napkins, or they can be integral with the materials of theabsorbent articles, e.g. by being integral extension of the topsheet,the backsheet or a combination thereof. If the wings are attached thenthey can be attached in a basic outward pointing position or already bepredisposed towards their in-use position, i.e. towards the longitudinalcenterline.

The thickness of the absorbent article of the present inventionespecially for panty liners is less than 3 mm, more preferably in therange of 0.5 to 1.5 mm and even most preferably in the range of 0.8 to1.3 mm according to the thickness measurement method described hereinbelow.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

Test method for total absorption capacity of the liquid absorbentthermoplastic composition

The total liquid absorption capacity of the liquid absorbentthermoplastic composition is determined as follows:

Principle:

The sample is weighed and submerged in the test solution for 10 minutesand afterwards weighted to determine the total absorption capacity.

Preparation of Saline Solution:

-   -   (9±0.1) g NaCl (saline solution 0.9%) is added to deionized        water to give a total mass of 1000 g±0.1 g and stirred until        dissolved.        Apparatus and materials:    -   1. Bag (100×50 mm) heatsealable polyester mesh, folded and heat        sealed on two (longer) of the three open sides so the inside        edges of the seals are about 3 to 5 mm from the edge of the bag.        Polyester mesh characteristic: Mass per unit area: 48 g/m²,        Thickness: 60 μm, Holes dimension: 18 μm, Open area: 13%, Yarn        diameter: 31 μm, Number of yarn: 200/cm. Suggested supplier:        Saatitech (www.saati.com); Reference material: PES18/13    -   2. Heat sealer capable of bonding polyester.    -   3. Analytical balance, capable of measuring a mass of 100 g to        an accuracy off 0.001 g.    -   4. Weigthing silicon paper.    -   5. Timer.    -   6. Beaker capable of containing 1 liter of solution.    -   7. Spatula.    -   8. Tweezers.

Sample Preparation

Starting from an absorbent article the liquid absorbent thermoplasticcomposition can be isolated with knwon means in order to be tested.Typically in an absorbent article the topsheet is removed from thebacksheet and both are separated from any additional layers if present.The liquid absorbent thermoplastic composition is scraped with a spatulafrom its substrate layer. The recovered thermoplastic composition willbe used to prepare samples as mentioned below with known means. Forexample, the thermoplastic composition can be melted, or dissolved witha suitable solvent. The recovered composition must be kept in a closedcontainer to avoid dust contamination and be allowed to equilibrate tothe temperature to run the test. The test conditions are 23° C.±2° C.and 50±10% relative humidity.

Procedure

-   -   1. Weigh 0.200 g±0.005 g of the liquid absorbent thermoplastic        composition and record the mass (Wd).    -   2. Prepare a sufficient number of bags (i.e., 6) to run the        required replicates.    -   3. Place each single test portion of 0.200 g±0.005 g of the        liquid absorbent thermoplastic composition into each single bag        and seal the bags opened side.    -   4. Prepare two blank bags (i.e. without any composition) and        test alongside the bags containing the thermoplastic        composition.    -   5. Fill the beaker with 0.9% saline solution.    -   6. Submerge the bags in the saline solution. Eliminate entrapped        air bubbles by manipulation of the bag.    -   7. After 10 minutes (±10 seconds), remove the bags from saline        solution and hang them freely to drain vertically till no liquid        is dripping from them.    -   8. Weigh each single bag recording the masses of the two blanks        (Wb) 1 and 2 and the masses of bags containing the absorbent        composition (Ww) 1, 2, . . . n.

Calculation and Results

Calculate the average of the two wet blank bags masses after absorption

Wb=(Wb1+Wb2)/2

For each sample calculate:

Abs (g/g)=(Ww−Wb−Wd)/Wd

Where:

Wd=dry test portion mass in g.Wb=average of 2 blank bag masses (after absorption) in g.Ww=mass of wet bag containing liquid absorbent thermoplastic compositionin g.

Dunk absorption capacity test for absorbent article

Purpose

This method measures the weight of a test fluid (Synthetic Urine B)which is retained in an absorbent article after it is immersed in thetest fluid for a certain period of time and after applying a staticpressure of 17 g/cm² on the article for 2 minutes.

Equipment

Item Supplier Magnetic stirrer, with a top IKAMAG or plate of 100 mmdiameter equivalent Magnetic stirring bar 64 mm IKAMAG or equivalentBeaker, 2000 ml capacity Hirshmann or equivalent Digital balance -accurate ±0.01 g Mettler or equivalent Timer control (stop watch)accurate to 0.5 sec Mali or equivalent Plexyglas plate and basin (atleast 2 cm deep), Fisher or at least 25 × 25 cm equivalent Plexyglasslope with 15° angle to the Convenient horizontal, at least 8 cm widesource Weight of 1320 (±15 g) with base dimensions Convenient of 15.5 ×5 cm source (equivalent to 17 g/cm²) with a foam base covered withplastic film Weight of 2265 g (±15 g) with base Convenient dimensions of20.5 cm × 6.5 cm with a foam source base covered with plastic film (forabsorbent article with large dimensions, e.g. long wings) A stand withan extendable arm to fix the Convenient weight on the slope and stop itfrom sliding source

Preparation of Synthetic Urine B Solution

Place a 2000 ml beaker on the balance. Weigh 800 g of demineralisedwater into the beaker. Carefully add into the beaker exact amounts ofthe following materials:

1) UREA (NH₂CO NH₂) 20.00 grams 2) Sodium Chloride (NaCl) 9.00 grams 3)Magnesium Sulfate (Mg So₄7H₂O) 1.10 grams 4) Calcium Chloride(CaCl₂2H₂O) 0.79 grams

Fill up to 1000 ml with mineralised water and mix the chemicals with aidof stemming bar on a magnetic stirrer. The resulting solution should becovered with parafilm to prevent evaporation or contamination.

Test Procedure

The following precautions should be followed during the test to ensureconsistent accuracy of the results:

-   -   The absorbent article should be kept flat without bending or        twisting in all steps of the test    -   The article should be held gently at the top while the load is        applied to prevent it from sliding. Applying the load should be        done carefully and gradually starting from the top of the sample    -   Ensure that the slope and base of the weight are dry before        placement of the article. Also ensure that the balance tray is        dry before weighing the wet absorbent article.    -   Pre-weigh the absorbent article (including release paper) using        the digital balance and record the ‘initial dry weight’ to an        accuracy of ±0.01 g.    -   Fill the basin partially with Syn. Urine B solution and ensure        that the depth of the solution in the basin throughout the test        is maintained higher than 5 mm.    -   Put the absorbent article face down in the basin for 25 minutes    -   Gently remove the absorbent article from the basin by holding it        from its edge. Allow it to drip for 2 seconds in a vertical        position, then place it face down on the slope with angle 15°.    -   Place the weight (10) gently on the article (11) for two minutes        (±5 sec) and use the arm (12) of the stand to fix the weight        (FIG. 10).    -   Remove the weight after the 2 minutes and hold the article from        the edge and allow it to drip in a vertical position for two        seconds, then re-weigh it and record the ‘wet weight’ to an        accuracy of ±0.01 g.        Calculation of capacity (Dunk)

Dunk (g)=wet weight (g)−the initial dry weight (g)

The absorption capacity reported for a given absorbent article is theaverage of the Dunk value measured on at least 6 absorbent articles.

The absorption capacity can be reported in grams per square cm of theabsorbent article tested as well as in grams per gram of absorbentarticle tested if desired.

Thickness Measurement

The thickness should always be measured at the thickest possible place,usually in the center of the absorbent article. For convenience themeasurement is conducted on the absorbent article inclusive anyprotective cover means present. The product should be reconditioned at50% humidity and 23° C. for two hours within its usual package and beremoved not more than five minutes prior to the measurement.

The thickness is measured with a micrometer gauge having a range of 0 to30 mm and capable of plus minus 0.5 mm tolerance. The gauge must not bespring loaded and should have a foot moving downwards under gravity. Themicrometer foot has a diameter of 40 mm and is loaded with a 80 gramweight. The measurement is taken between 5 and 10 seconds after the foothas been lowed to come into contact with the absorbent article.Measurements should be taken often enough to allow statistical analysisto determine average thickness within a sigma of plus minus 0.1 mm. Adetailed description of the thickness measurement can also be found inU.S. Pat. No. 5,009,653.

Water Absorption Test

The determination of the water absorption of thermoplastic polymericbase material used in preferred embodiment herein is conducted accordingto the standard test method ASTM D 570-81 with the following conditions.The measurement of water absorption for thermoplastic polymeric basematerial is made on a sample of the material in form of a film 76.2 mmlong by 25.4 mm wide by 0.2 mm thick. For all materials a 24 hoursimmersion in distilled water at 23° C. is chosen and the percentage ofwater absorbed in accordance with the ASTM D 570-81 standard isreported.

Tensile Strength Test

The test measures the mechanical resistance of a sample of material astensile strength at break, according to the standard test method ASTM D412-92, under the following conditions. The test is performed on samplesmade of the liquid absorbent thermoplastic composition and having alength of 130 mm, a width of 25.4 mm, and a thickness of 2 mm, and beingcontinuous, obtained with any suitable method, for example by pouringthe liquid absorbent thermoplastic composition in molten state at asuitable temperature, e.g. 180° C. for the compositions of Examples 2 or3, into a metallic pan lined with release paper in a continuous layerhaving a thickness of 2 mm, and then after cooling cutting from thislayer the samples of the desired dimensions.

The test is performed on samples made of the same composition both indry and in wet state. In order to prepare the samples in wet state asample is placed in a container of a saline solution (e.g. 0.9% NaCldistilled water solution) maintained at a temperature of 23±1° C., andshall rest entirely immersed for ten minutes. At the end of ten minutes,the sample shall be removed from the water, all surface water wiped offwith a dry cloth, and tested for wet tensile strength as provided in thestandard test method.

Sample Preparation

When starting from an absorbent article comprising the liquid absorbentthermoplastic composition in turn comprising the matrix of thermoplasticpolymeric base material with particles of water-insolublewater-swellable absorbent material dispersed therein, for example adisposable absorbent article with the thermoplastic composition coatedonto a substrate, the thermoplastic composition can be isolated withknown means in order to be tested. Typically in a disposable absorbentarticle the topsheet is removed from the backsheet and both areseparated from any additional layers if present. The liquid absorbentthermoplastic composition is scraped with a spatula from its substratelayer. The recovered thermoplastic composition will be used to preparesamples as mentioned above with known means. For example, thethermoplastic composition can be melted, or dissolved with a suitablesolvent. Particles of absorbent material can be also separated from thethermoplastic composition, in order to isolate the thermoplasticpolymeric base material, as it is known in the art, for example bysuitably sieving or filtering from the molten state, or preferably fromthe solution.

Examples for the liquid absorbent thermoplastic composition according tothe present invention are as follow:

Example 1

A liquid absorbent thermoplastic composition representative of presentinvention is following mixture, forming a hot-melt adhesive:

18% Estane T5410 from Noveon 17% PEG E400 from Dow Chemical  1% IrganoxB 225 from Ciba Speciality Chemicals 19% CR00 (former PM17) from Savare45% Aquakeep 10 SH-NF ® from Sumitomo-Seika.

Estane T5410 is a polyurethane-hydrophilic thermoplastic polymer, PEG E400 is a polyethylene glycol (plasticizer, MW about 400), Irganox B 225an anti oxidant and CR 00 is commercially available adhesive hotmelt.

Example 2

A thermoplastic polyether-amide block copolymer available from Atofina(France) under the trade name Pebax MV 3000 is compounded withpolyethylene glycol PEG 400 (plasticiser, MW about 400), Sodium DodecylSulphate, both available from Aldrich Co., and Irganox B 225 (antioxidant agent) available from Ciba-Geigy. The formulation in percent byweight has the following composition, and constitutes the thermoplasticpolymeric base material:

28.6% Pebax MV 3000 68.6% PEG 400 1.4% SDS 1.4% Irganox B 225

The thermoplastic polymeric base material has a water absorption of 43%,value measured according to the Water Absorption Test described herein.The thermoplastic base material is formed into a film to be used in theWater absorption Test by melt coating the thermoplastic base material ata temperature of 180° C. onto a release paper to obtain a film havingthe prescribed thickness of 200 μm. After cooling at room temperaturethe film is separated from the release paper.

A superabsorbent material in particle form, sold under the trade nameAqua Keep 10SH-NF by Sumitomo Seika Chemical (Japan) (average particlesize between 20 and 30 μm and being in form of spherical beads), isadded to the thermoplastic polymeric base material while maintained at atemperature of 180° C. and uniformly dispersed, in an amountcorresponding to 42.9% by weight of the above thermoplastic polymericbase material. This example of the liquid absorbent thermoplasticcomposition has the following final composition by weight:

20% Pebax MV 3000 48% PEG 400 30% Aqua Keep 10SH-NF  1% SDS  1% IrganoxB 225

Example 3

A thermoplastic polyether-ester block copolymer available from Du Pont(USA) under the trade name Hytrel 8171 is compounded with polyethyleneglycol PEG 400 (plasticiser, MW about 400), polyethylene glycol PEG 1500(plasticiser, MW about 1500), both available from Aldrich Co., andIrganox B 225 (anti oxidant agent) available from Ciba-Geigy. Theformulation in percent by weight has the following composition, andconstitutes an alternative thermoplastic polymeric base material:

28.6% Hytrel 8171 21.4% PEG 400 48.6% PEG 1500 1.4% Irganox B 225

The thermoplastic polymeric base material has a water absorption of 96%,value measured according to the Water Absorption Test described herein.The thermoplastic base material is formed into a film to be used in theWater absorption Test by melt coating the thermoplastic base material ata temperature of 180° C. onto a release paper to obtain a film havingthe prescribed thickness of 200 μm. After cooling at room temperaturethe film is separated from the release paper.

A superabsorbent material in particle form sold under the trade nameAqua Keep 10SH-NF by Sumitomo Seika Chemical (Japan) is added to thethermoplastic polymeric base material while maintained at a temperatureof 180° C. and uniformly dispersed, in an amount corresponding to 42.9%by weight of the thermoplastic polymeric base material. As anotherillustrative example of the present invention, the resulting liquidabsorbent thermoplastic composition has the following final compositionby weight:

20% Hytrel 8171 15% PEG 400 34% PEG 1500 30% Aqua Keep 10SH-NF  1%Irganox B 225

All these compositions (Examples 1 to 3) have respectively a tensilestrength in wet state which is at least 35% of the tensile strength ofthe composition in dry state, when evaluated according to the Tensilestrength test described herein. All these compositions (Examples 1 to 3)have respectively a total absorption capacity towards saline solution(0.9%) of more than 5 grams per gram when measured according to testdescribed herein before.

Examples of absorbent articles according to the present invention aredescribed herein after:

Example 4

A panty liner as illustrated in FIGS. 1 and 2 comprises an aperturedpolyethylene formed film topsheet (1) (code name X-28278 available fromTredegar), a spiral layer of adhesive (2) (D3151 available from Fuller),an absorbent element made of a fluid distribution nonwoven material (3)(carded bico Sawabond VP40/01/11 available from Sandler) together with astorage layer (4) consisting of plurality of spaced apart zones of aliquid absorbent thermoplastic composition of Example 1 above (basisweight of 152 g/m²), said zones having the form of stripes of 2 mmwidth, a plastic polyethylene film backsheet (5) without pigment (code14/18020, available from RKW), panty fastening adhesive (6) (HL1461available from Fuller) and release liner (7). The topsheet, the fluiddistribution layer and backsheet are substantially coextensive with eachother and are attached to each other along the outer edge of theso-formed napkin by heat bonding C.

The total absorption capacity of this pantiliner as measured per Dunkabsorption test described herein is of 7 grams towards Synthetic urineB.

In this pantiliner the liquid absorbent thermoplastic composition ofExample 1 configured in stripes represents 75% by weight of the totalweight of the absorbent element (i.e., fluid distribution layer andstorage layer).

Example 5

A sanitary napkin comprises an apertured polymeric film topsheet (CPMRIS coded 1035025 available from Tredegar, as the fluid distributionlayer a 40 g/m² BICO thermalbonded carded nonwoven (coded Sawabond 4313)from Sandler underlying the topsheet, a storage layer made of stripes ofthe liquid absorbent thermoplastic composition of Example 2 above and apolyethylene backsheet (coded RKPA) from RKW. The topsheet, the fluiddistribution layer and backsheet are substantially coextensive with eachother and are attached to each other along the outer edge of theso-formed napkin by heat bonding.

Example 6

A sanitary napkin as in Example 5, said napkin comprising in addition tothe element mentioned in Example 5a fibrous layer underlying the storagelayer, i.e., between the storage layer and the backsheet. This fibrouslayer is a spunlaced nowoven layer.

The total absorption capacity of the sanitary napkin of Examples 5 and 6as measured per Dunk absorption test described herein towards Syntheticurine B is of more than 10 grams. In the sanitary napkin of Example 6the liquid absorbent thermoplastic composition of Example 2 configuredin stripes represents 65% by weight of the total weight of the absorbentelement (i.e., fluid distribution layer, storage layer and fibrouslayer).

Other examples illustrating the present invention include for examplethe pantiliner of Example 4, wherein the liquid absorbent thermoplasticcomposition used is either the one of Examples 2 or 3 instead of the oneof Example 1 above as well as the sanitary napkin of Example 5 or 6,wherein the liquid absorbent thermoplastic composition used is eitherthe one of Example 1 or 3 instead of the one of Example 2.

All documents cited in the Detailed Description of the invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. An absorbent article comprising a topsheet a backsheet and anabsorbent element positioned between the topsheet and the backsheet, theabsorbent element comprising a liquid absorbent thermoplasticcomposition which comprises a polymeric base material having particlesof water-insoluble water swellable absorbent material dispersed therein,wherein the liquid absorbent thermoplastic composition has a totalabsorption capacity of at least 2 grams per gram and is configured in afirst zone and a second zone that is spaced apart from the first zone bya distance of between 0.5 mm and 10 mm.
 2. The absorbent article ofclaim 1, wherein the polymeric base material comprises a polyglycol. 3.The absorbent article of claim 1, wherein the water-insoluble waterswellable absorbent material comprises a starch.
 4. The absorbentarticle of claim 1, wherein the polymeric base material comprises apolyglycol and the water-insoluble water swellable absorbent materialcomprises a starch.
 5. The absorbent article of claim 1, wherein thewater-insoluble water swellable absorbent material is present in anamount from 30% to 70% by weight of the total liquid absorbentthermoplastic composition.
 6. The absorbent article of claim 1, whereinthe water-insoluble water swellable absorbent material is present in anamount from 40% to 60% by weight of the total liquid absorbentthermoplastic composition.
 7. The absorbent article of claim 1, whereinthe liquid absorbent thermoplastic composition is devoid of a tackifyingresin.
 8. The absorbent article of claim 1, wherein the first and secondzones are in the form of stripes being rectilinear or curved, dots,circles, squares, rectangles, triangles, lozenges, spirals and theircombination.
 9. An absorbent article comprising a topsheet a backsheetand an absorbent element positioned between the topsheet and thebacksheet, the absorbent element comprising a liquid absorbentthermoplastic composition which comprises a polymeric base materialhaving particles of water-insoluble water swellable absorbent materialdispersed therein, wherein the liquid absorbent thermoplasticcomposition is configured in a plurality of unattached spaced apartzones and is devoid of a tackifying resin.
 10. The absorbent article ofclaim 9, wherein the polymeric base material comprises a polyglycol. 11.The absorbent article of claim 9, wherein the water-insoluble waterswellable absorbent material comprises a starch.
 12. The absorbentarticle of claim 9, wherein the polymeric base material comprises apolyglycol and the water-insoluble water swellable absorbent materialcomprises a starch.
 13. The absorbent article of claim 9, wherein thewater-insoluble water swellable absorbent material is present in anamount from 30% to 70% by weight of the total liquid absorbentthermoplastic composition.
 14. The absorbent article of claim 9, whereinthe water-insoluble water swellable absorbent material is present in anamount from 40% to 60% by weight of the total liquid absorbentthermoplastic composition.
 15. The absorbent article of claim 9, whereinthe first and second zones are in the form of stripes being rectilinearor curved, dots, circles, squares, rectangles, triangles, lozenges,spirals and their combination.
 16. The absorbent article of claim 9,wherein the liquid absorbent thermoplastic composition has a totalabsorption capacity of at least 1 gram per gram.
 17. An absorbentarticle comprising a topsheet a backsheet and an absorbent elementpositioned between the topsheet and the backsheet, the absorbent elementcomprising a liquid absorbent thermoplastic composition which comprisesa polymeric base material having particles of water-insoluble waterswellable absorbent material dispersed therein, wherein thewater-insoluble water swellable absorbent material comprises a starch,and wherein the liquid absorbent thermoplastic composition is configuredin a first zone and a second zone that is spaced apart from the firstzone by a distance of between 0.5 mm and 10 mm.
 18. The absorbentarticle of claim 17, wherein the polymeric base material comprises apolyglycol.
 19. The absorbent article of claim 17, wherein the liquidabsorbent thermoplastic composition has a total absorption capacity ofat least 1 gram per gram.
 20. The absorbent article of claim 17, whereinthe liquid absorbent thermoplastic composition is devoid of a tackifyingresin.